package DBLayer;

import java.sql.*;

public class DbConnection
{
	//Constant used to get access to the database
	
	//SQL Server connection
	private static final String driver = "jdbc:sqlserver://balder.ucn.dk:1433";
	private static final String databaseName = ";databaseName=dm76_5";
	
	private static String userName = ";user=DM76_5";
	private static String password = ";password=MaaGodt";
	//SQL Server connection
	  
	private DatabaseMetaData dma;
	private static Connection con;
	// an instance of the class is generated
	private static DbConnection instance = null;

	// the constructor is private to ensure that only one object of this class is created
	private DbConnection()
	{
	  	String url = driver + databaseName + userName + password;
        try
        {
        	//load af driver
	        //SQL Server
	        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
	        System.out.println("Load af class ok");
        }
	    catch(Exception e)
	    {
	        System.out.println("Can not find the driver");
	        System.out.println(e.getMessage());
	    }//end catch
	    try
	    {
	        //connection to the database
	        con = DriverManager.getConnection(url);
	        //set autocommit
	        con.setAutoCommit(true);
	        dma = con.getMetaData(); // get meta data
	        System.out.println("Connection to " + dma.getURL());
	        System.out.println("Driver " + dma.getDriverName());
	        System.out.println("Database product name " + dma.getDatabaseProductName());
	    }//end try
	    catch(Exception e)
	    {
	        System.out.println("Problems with the connection to the database");
	        System.out.println(e.getMessage());
	        System.out.println(url);
	    }//end catch
	}//end  constructor
    //closeDb: closes the connection to the database
	public static void closeConnection()
	{
	  	try
	  	{
	        con.close();
	        System.out.println("The connection is closed");
	    }
	    catch (Exception e)
	    {
	        System.out.println("Error trying to close the database " +  e.getMessage());
	    }
	}//end closeDB
			
	//getDBcon: Get-metode, returnerer forbindelsen til databasen
	public  Connection getDBcon()
	{
	   return con;
	}
	//this method is used to get the instance of the connection
	public static DbConnection getInstance()
	{
	    if (instance == null)
	    {
	        instance = new DbConnection();
	    }
	    return instance;
	}
	public static void startTransaction()
	{
		try
		{
	        con.setAutoCommit(false);
	    }
	    catch(Exception e)
	    {
	        System.out.println("fejl start transaction");
	        System.out.println(e.getMessage());
	    }
	}
	public static void commitTransaction()
	{
		try
		{
	        con.setAutoCommit(true);
	    }
	    catch(Exception e)
	    {
	        System.out.println("fejl commit transaction");
	        System.out.println(e.getMessage());
	    }
	}
	public static void rollbackTransaction()
	{
		try
		{
	        con.rollback();
	        con.setAutoCommit(true);
	    }
	    catch(Exception e){
	        System.out.println("fejl rollback transaction");
	        System.out.println(e.getMessage());
	    }
	}
}//end DbConnection